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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Why couldn't an operating system be written in ada
Date: Tue, 26 Feb 2019 10:30:36 +0100
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Xref: reader01.eternal-september.org comp.lang.ada:55670
Date: 2019-02-26T10:30:36+01:00
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On 2019-02-26 09:46, Niklas Holsti wrote:
> On 19-02-25 23:56 , Rabican wrote:
>> On Saturday, July 13, 1996 at 3:00:00 AM UTC-4, Mark  McKinney wrote:
>>> It has been claimed that the capability to interface with other 
>>> languages
>>> is a great asset to ada. Sometimes interfacing can be a tremendous
>>> liability. Besides the OS could perform most of work that the language
>>> runtime does. So why not build an OS in ADA?
>>
>> yeah why not?  anything?
> 
> This has been discussed many times before in comp.lang.ada.
> 
> The first question is not "why not build an OS is Ada", the first 
> question is "why build a new OS at all"?
> 
> Then, if a new OS is going to be built for some reason, we can ask which 
> language should be used, and of course (IMO) Ada would be a strong 
> contender. However, for larger systems, the OS must usually implement a 
> "process" concept that goes beyond Ada tasking and provides isolation 
> between different users and applications. This means that the OS will 
> have a process/service-level API that is not, as such, Ada-language 
> specific. And so the fact that the OS is implemented in Ada becomes 
> invisible on the application level.
> 
> This is not to say that an OS API specified in Ada could not be an 
> improvement (for Ada applications) on the current OS APIs which are 
> usually specified in C. However, such an Ada OS API could also be 
> provided for an OS implemented in C or some other language.

Right. This is a general problem only tangentially related to Ada. The 
purely procedural OS API outlived their time.

A new generation of OSes must have higher-level API which would include 
tasking and synchronization primitives as well as other abstract types 
types. Call it OO or not, but that is beyond procedures, ints and void *.

The world is not ready for this and the languages, Ada included, are not 
mature enough either.

So, yes, one can write an C-esque OS in Ada, but who needs yet another 
horse cart?

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de